U.S. patent application number 10/673884 was filed with the patent office on 2004-04-01 for stacked stator core and method of manufacturing thereof, and rotary motor and method of manufacturing thereof.
This patent application is currently assigned to MITSUBISHI DENKI KABUSHIKI KAISHA. Invention is credited to Hashimoto, Akira, Matsui, Akio, Miyake, Nobuaki, Motohashi, Masaya, Nakahara, Yuji, Nakanishi, Yasuyuki.
Application Number | 20040061407 10/673884 |
Document ID | / |
Family ID | 18746619 |
Filed Date | 2004-04-01 |
United States Patent
Application |
20040061407 |
Kind Code |
A1 |
Miyake, Nobuaki ; et
al. |
April 1, 2004 |
Stacked stator core and method of manufacturing thereof, and rotary
motor and method of manufacturing thereof
Abstract
The present invention relates to a structure of a stacked stator
core formed when rotary motors are manufactured and to a method of
manufacturing the stacked stator core. It is possible to improve
the workability in the winding process and the productivity of the
stator and the rotary motor because the stacked stator core
includes a plurality of stator cores 300, each of which is made up
of a prescribed number of stacked sheet magnetic materials, a
plurality of yoke members 301 forming each stator core, a bendable
bent portion 304 provided between the yoke members, and an
interconnecting portion 401 for connecting the plurality of stator
cores 300 one another while providing a difference in level, by
connecting the top end of one stator core with the bottom end of
the other stator core.
Inventors: |
Miyake, Nobuaki; (Tokyo,
JP) ; Matsui, Akio; (Tokyo, JP) ; Nakahara,
Yuji; (Tokyo, JP) ; Nakanishi, Yasuyuki;
(Tokyo, JP) ; Hashimoto, Akira; (Tokyo, JP)
; Motohashi, Masaya; (Tokyo, JP) |
Correspondence
Address: |
BURNS DOANE SWECKER & MATHIS L L P
POST OFFICE BOX 1404
ALEXANDRIA
VA
22313-1404
US
|
Assignee: |
MITSUBISHI DENKI KABUSHIKI
KAISHA
|
Family ID: |
18746619 |
Appl. No.: |
10/673884 |
Filed: |
September 30, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10673884 |
Sep 30, 2003 |
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10111701 |
Apr 29, 2002 |
|
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10111701 |
Apr 29, 2002 |
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PCT/JP01/07309 |
Aug 27, 2001 |
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Current U.S.
Class: |
310/254.1 ;
29/596 |
Current CPC
Class: |
H02K 1/185 20130101;
Y10T 29/49009 20150115; H02K 3/522 20130101; H02K 15/022 20130101;
H02K 15/095 20130101; Y10T 29/49073 20150115; H02K 1/14 20130101;
H02K 1/148 20130101; Y10T 29/49071 20150115; H02K 15/026
20130101 |
Class at
Publication: |
310/216 ;
310/259; 029/596 |
International
Class: |
H02K 001/00; H02K
015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 29, 2000 |
JP |
2000-258286 |
Claims
What is claimed is:
1. A stacked stator core, comprising: a plurality of stator cores,
each making up of a prescribed number of stacked sheet magnetic
materials; a plurality of yoke members forming each stator core; a
bendable bent portion provided between said yoke members; and a
connecting member, provided between the upper end of one stator
core and the lower end of the other stator core, for
interconnecting said plurality of stator cores.
2. A disk drive unit, comprising: a plurality of yoke members, each
yoke member making up of a prescribed number of stacked sheet
magnetic materials; a bendable bent portion provided between said
yoke members; a stator core provided with a stepped yoke member
whose one part is shifted by a prescribed number in the stacking
direction of said plate magnetic materials relative to another yoke
member; a stator formed by bending said stator core in a ring and
connected both ends of said stator core; a base equipped with said
stator; and a portion for reading and writing data from and to
magnetic recording media rotated by said rotary motor.
Description
[0001] This application is a divisional of application Ser. No.
10/111,701, filed Apr. 29, 2002, which in turn is a .sctn.371
application of PCT/JP01/07309, filed Aug. 27, 2001.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a rotary motor and a stator
used for driving a medium used in a magnetic disk drive unit,
optical disk drive unit or the like. More particularly, the present
invention relates to the structure of the rotary motor and the
stator in order to improve the mass productivity and to a method of
manufacturing thereof.
[0004] 2. Description of Related Art
[0005] A conventional rotary motor stator of this type (not shown)
manufactured by stacking a plurality of ring-shaped board members
blanking directly from a steel board, as disclosed in
JP-A-100823/1982, for instance. However, yield of materials is low.
For this reason, JP-B-46620/1985 discloses the improved yield by
winding a belt-shaped board member with a large number of teeth in
spiral while plastically deforming the board member to fasten a
several layers by welding the respective layers.
[0006] As an another conventional method of manufacturing the
rotary motor, there is a method disclosed in JP-A-98774/1999. FIGS.
48 and 49 are a view showing such a method.
[0007] Referring to FIGS. 48 and 49, the method involves feeding a
strip-shaped magnetic material 500 to a press machine 502 through a
work feeding machine 501, forming a core member 503 consists of
thinned portions 503a, yoke members 503b, and magnetic pole teeth
503c, forming ring-shaped stacked yoke members 505 by winding a
reel 504 by a plurality of turns such that the core member 503
corresponding to a plurality of stator cores are arranged during
one turn, winding driving coils 506, dividing ring-shaped stacked
yoke member 505 into blocks such that a stator core 507
corresponding to one rotary motor is provided, and producing
stators for rotary motors by bending the stator core 507 with a
tool.
[0008] The conventional rotary motor stators are constructed as
above. Thus, the stator disclosed in JP-A-100823/1982 has not only
the low yield of materials as mentioned above, but also is heavy to
assemble thereof as the assembly forces a great number of the board
members to be grasped one by one for conveyance. The stator
disclosed in JP-B-46620/1985 has a difficulty in unfolding and
dividing the stators for winding as the belt-shaped board member is
wound up in spiral while plastically deforming. Regardless, they
lack productivity.
[0009] Moreover, the method of manufacturing rotary motors
disclosed in JP-A-98774/1999 has also the following problems.
[0010] (1) The diameter of connected stator cores 507 is very large
compared with the thickness of stacked yoke member 505 for the
reason that stator cores 507 corresponding to a plurality of rotary
motors are connected in the circumferential direction. Therefore,
the stacked yoke members 505 are apt to sag, which makes worse
handling of stacked yoke members 505 in coating them with
insulation coating and placing them onto the winding machine.
[0011] (2) It is difficult to provide a positioning portion for
mounting the stator core 507 on the rotary motor and a
stator-connecting for forming the stator core 507 in a ring and
holding it for the reason that the yoke members having the same
shape are continuously produced and they are wound up.
[0012] (3) The magnetic pole teeth 503c are stacked on the slant
for the reason that the strip-shaped magnetic material 500 is
provided with yoke members and the strip-shaped magnetic material
500 is wound up in a spiral form around a reel to form stacked yoke
members 505. As a result, this incurs the deteriorated productivity
in the winding process, and the decreased driving torque of the
rotary motor and the torque ripple thereof.
[0013] The present invention has been made to solve the above
problems. An object of the invention is to provide a stacked stator
core capable of improving the workability in the winding process
and the productivity of the product and a method of manufacturing
the stator, and a rotary motor equipped with the stator and a
method of manufacturing the rotary motor.
SUMMARY OF THE INVENTION
[0014] The stacked stator core to according to the present
invention includes a first core member formed by stacking a
prescribed number of magnetic materials and made up of a plurality
of yoke members connected to one another through a bendable bent
portion; a second core member formed by stacking the prescribed
number of magnetic materials and made up of a yoke member arranged
in such a manner that one end of each magnetic material of the
second core member is successively connected to the other end of
the first core member through a bendable bent portion from the next
magnetic material of the other end of the first core member by
shifting entirely the second core member downwards, with left the
same number of stages of one end of the second core member
unconnected as the prescribed number of stages; a third core member
formed by stacking the prescribed number of magnetic materials,
each of which is made up of the same number of yoke members as the
first core member connected through the bendable bent portion, and
one end of the magnetic material of the third core member is
connected to the other end of the second core member through a
bendable bent portion by shifting entirely the third core member
downwards; and a fourth core member formed by stacking the
prescribed number of magnetic materials and made up of a yoke
member arranged in such a manner that one end of each magnetic
material of the fourth core member is successively connected to the
next stage of the other end of the third core member through a
bendable bent portion from the next magnetic material of the other
end of the third core member by shifting entirely the fourth core
member downwards, with left the same number of stages of one end of
the fourth core member unconnected as the prescribed number of
sages; wherein the first, the second, the third and the fourth core
members are independently arranged in a ring and mutually
stacked.
[0015] This provides a stacked stator core able to easily unfold
and divide winding.
[0016] The method of manufacturing a stator according to the
present invention, includes the steps of forming the stacked stator
core by blanking a magnetic material of Claim 1 using a progressive
die; unfolding the stacked stator core straight; subjecting the
straight stacked stator core to a prescribed treatment; winding a
wire around the straight stacked stator core subjected to the
prescribed treatment; and winding up the straight wire-wound
stacked stator core to restore the core to its original arrangement
in a ring.
[0017] This provides a method of manufacturing a stator able to
improve the workability in the winding process and the mass
productivity.
[0018] The method of manufacturing a stacked stator core according
to the present invention includes a plurality of stator cores, each
of which is made up of a prescribed number of stacked sheet
magnetic materials; a plurality of yoke members forming each stator
core; a bendable bent portion provided between the yoke members;
and an interconnecting portion for interconnecting the plurality of
stator cores by connecting the upper end of one stator core to the
lower end of the other stator core with a difference in level
provided between the plurality of stator cores.
[0019] This provides a stator core able to easily unfold and divide
wiring.
[0020] The method of manufacturing a rotary core according to the
present invention includes a stator connected both ends of the
stator core by bending a stator core in a ring having a plurality
of stator cores, each made up of a prescribed number of stacked
sheet magnetic materials; a plurality of yoke members forming each
the stator core; a bendable bent portion provided between the yoke
members; and an interconnecting portion for interconnecting the
plurality of stator cores by connecting the upper end of one stator
core to the lower end of the other stator core with a difference in
level provided between the plurality of stator cores; and a base
member equipped with the stator core.
[0021] This provides a rotary motor superior in the mass
productivity.
[0022] The disk drive unit according to the present invention
includes a stator core divided from a stacked stator core provided
with a plurality of stator cores, each stator core makde up of a
prescribed number of stacked sheet magnetic materials; a plurality
of yoke members forming each stator core; a bendable bent portion
provided between the yoke members; an interconnecting portion for
interconnecting the plurality of stator cores by connecting the top
of one stator core to the bottom of the other stator core with a
difference in level provided between the plurality of stator cores;
and a portion for reading and writing data from and to magnetic
recording media rotated by the rotary motor.
[0023] This provides a slim and low-cost disk drive unit.
[0024] The method of manufacturing a rotary motor according to the
present invention includes the steps of stacking a prescribed
number of ring-shaped sheet magnetic materials provided with a
plurality of yoke members and having a first divided portion at one
place between the yoke members and a bent portion at the other
place therebetween, such that each first divided portion is placed
at the same position; stacking a prescribed number of sheet
magnetic materials such that second divided portions thereof are
placed with a prescribed number shifted by a unit of yoke members
in the circumferential direction relative to the prescribed number
of stacked sheet magnetic materials; successively stacking the
sheet magnetic materials to form a stacked stator core by repeating
the two steps as many as a desired number of times; elongating the
bent portions of the stacked stator core to unfold the stacked
stator core straight; winding driving coils around the magnetic
pole teeth provided on the yoke members; dividing the wound yoke
members into stator blocks; and forming a ring-shaped stator by
bending the divided stator at the bending portion and connecting
both ends thereof.
[0025] This provides the workability in the winding process and the
mass productivity of a stator and rotary motor.
[0026] The method of manufacturing a rotary motor according to the
present invention includes stacking a prescribed number of
ring-shaped sheet magnetic materials provided with a plurality of
yoke members and having a bent portion between the yoke members and
a first divided portion in the vicinity of one the bent portion,
such that each first divided portion is placed at the same
position; stacking a prescribed number of sheet magnetic materials
having a second divided portion at the position opposed to the
first divided portion through the bent portion on the stacked sheet
magnetic materials, such that each second divided portion is placed
at the same position; stacking a prescribed number of sheet
magnetic materials such that third divided portions thereof are
positioned with a prescribed number shifted by a unit of yoke
members in the circumferential direction relative to the prescribed
number of stacked sheet magnetic materials having the second
divided portion; successively stacking the sheet magnetic materials
to form a stacked stator core by repeating the three steps as many
as a desired number of times. elongating the bent portions of the
stacked stator core to unfold the stacked stator straight; winding
driving coils around the magnetic pole teeth provided on the yoke
members; dividing the wound yoke members into stator blocks; and
forming a ring-shaped stator by bending the divided stator at the
bending portion and connecting both ends thereof.
[0027] This improves the workability in the winding process and the
mass productivity of a rotary motor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a perspective view showing the partially unfolded
structure of the stacked stator core according to a first
embodiment of the present invention;
[0029] FIG. 2 is a front view showing the partially unfolded
structure of the stacked stator core shown in FIG. 1;
[0030] FIG. 3 is a sectional view showing the section taken along
line III-III in FIG. 2;
[0031] FIG. 4 is a sectional view showing the section taken along
line IV-IV in FIG. 2;
[0032] FIG. 5 is a perspective view showing a step of manufacturing
the stator by the stacked stator shown in FIG. 1;
[0033] FIG. 6 is a perspective view showing the second step of
manufacturing the stator shown in FIG. 5 different from FIG. 5;
[0034] FIG. 7 is a perspective view showing the third step of
manufacturing the stator shown in FIG. 5;
[0035] FIG. 8 is a perspective view showing the fourth step of
manufacturing the stator shown in FIG. 5;
[0036] FIG. 9 is a plan view showing the structure of the stator
manufactured by going through each step;
[0037] FIG. 10 is a perspective view of the rotary motor;
[0038] FIG. 11 is a perspective view of the stator used for the
rotary motor;
[0039] FIG. 12 is a partially enlarged view of the unfolded
stator;
[0040] FIG. 13 is a partially enlarged view of the unfolded stator
core;
[0041] FIG. 14 is an exploded perspective view of the rotary
motor;
[0042] FIG. 15 is a perspective view of the stacked stator core
used for the stator core of the rotary motor;
[0043] FIG. 16 is a partially unfolded perspective view of the
stacked stator core;
[0044] FIG. 17 is a schematic view of the elongated stacked stator
core;
[0045] FIG. 18 is a perspective view showing the state in which the
magnetic materials of the stacked stator core are stacked;
[0046] FIG. 19 is a schematic view showing the application of
insulation coating to the stacked stator core;
[0047] FIG. 20 is a partially enlarged view of the stacked stator
core;
[0048] FIG. 21 is a perspective view showing the steps in which the
stator cores are divided from the stacked stator core and the
driving coils are wound around the stator core;
[0049] FIG. 22 is a perspective view showing the steps in which the
driving coils are wound around the divided stator core and formed
in a ring;
[0050] FIG. 23 is a partially enlarged view in the vicinity of the
bent portion of the stator core and a sectional view thereof;
[0051] FIG. 24 is a plan view showing the angle pitches of the
magnetic pole teeth;
[0052] FIG. 25 is a view showing the method of manufacturing
stators after the driving coils are wound;
[0053] FIG. 26 is a view showing the state in which the rotor of
the rotary motor is provided with the cover table according to a
second embodiment;
[0054] FIG. 27 is a view showing the sectional structure in which
the number of coil winding of the driving coil wound around the
magnetic pole teeth of the stepped yoke member is smaller than that
of the yoke member;
[0055] FIG. 28 is a view showing the sectional structure in which
the stator is mounted on the base with a gradient such that the
step yoke member side is lower than the level shown in FIG. 26 and
the height Hh of the top surface of the driving coil wound around
the magnetic pole teeth of the step yoke member is the same as the
height Hf of the top surface of the driving coil wound around the
magnetic pole teeth of the yoke member;
[0056] FIG. 29 is a view showing the method of eliminating the
difference in level of the step yoke member by press-forming the
step yoke member;
[0057] FIG. 30 is a view showing the method of eliminating the
difference in level of the step yoke member by press-forming the
step yoke member;
[0058] FIG. 31 is a view showing the method of eliminating the
difference in level of the step yoke member by press-forming the
step yoke member;
[0059] FIG. 32 is a perspective view of the rotary motor;
[0060] FIG. 33 is a perspective view of the stator for the rotary
motor;
[0061] FIG. 34 is a partially enlarged view of the unfolded
stator;
[0062] FIG. 35 is a partially enlarged view of the unfolded stator
core;
[0063] FIG. 36 is a perspective view showing the state in which the
stacked stator core is partially unfolded;
[0064] FIG. 37 is a schematic view of the elongated stacked stator
core;
[0065] FIG. 38 is a perspective view showing how the magnetic
materials of the stacked stator core are stacked;
[0066] FIG. 39 is a perspective view showing the steps in which the
driving coils are wound around the stator core divided from the
stacked stator core and the stator sore is formed in a ring;
[0067] FIG. 40 is a perspective view showing the step in which the
stator is mounted on the base;
[0068] FIG. 41 is a perspective view showing the state in which the
stacked stator core is partially unfolded;
[0069] FIG. 42 is a schematic view of the elongated stacked stator
core;
[0070] FIG. 43 is a perspective view showing the steps in which the
driving coils are wound around the stator core divided from the
stacked stator cores;
[0071] FIG. 44 is a plan view showing the state in which the stator
core is formed in a ring;
[0072] FIG. 45 is a partial plan view showing the state in which
the yoke members are unfolded at the bent portion;
[0073] FIG. 46 is a sectional view of the bent portion;
[0074] FIG. 47 is an external view of the floppy disk drive unit
equipped with the rotary motor manufactured based on the stacked
stator core according to the above embodiments;
[0075] FIG. 48 is a view showing a part of steps in a conventional
method of manufacturing stators; and
[0076] FIG. 49 is a view showing a part of steps in a conventional
method of manufacturing stators.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
[0077] The first embodiment of the present invention will next be
described with reference to the drawings. FIG. 1 is a partially
unfolded perspective view showing the structure of the stacked
stator core in the first embodiment of the present invention. FIG.
2 is a front view showing the structure of the stacked stator core
shown in FIG. 1. FIG. 3 is a sectional view showing the section
taken along line III-III in FIG. 2. FIG. 4 is a sectional view
showing the section taken along line IV-IV in FIG. 2. FIG. 5 is a
perspective view showing a step of manufacturing the stator by the
stacked stator shown in FIG. 1. FIG. 6 is a perspective view
showing the second step of manufacturing the stator different from
FIG. 5. FIG. 7 is a perspective view showing the third step of
manufacturing the stator shown in FIG. 5. FIG. 8 is a perspective
view showing the fourth step of manufacturing the stator shown in
FIG. 5. FIG. 9 is a plan view showing the structure of the stator
manufactured by going through each step.
[0078] Referring to the FIGS. 1 to 8, reference numeral 10 denotes
a first core member 10 formed by stacking, for instance, five
magnetic materials and made up of three yoke members 1,2 and 3
connected to one another through a thinned portion m as a bendable
bent portion. The yoke members 1 and 3 have on one side a plurality
of projecting pole teeth 1a and 3a, and the yoke member 2 has on
one side a plurality of projecting edges 2a for twinning the
terminal of a winding to be described later.
[0079] Reference numeral 20 denotes a second core member formed by
stacking five magnetic materials similar to the first core member
10 and made up of yoke members 4 arranged in such a manner that one
end of each magnetic material of the second core member 20 is
successively connected to the second stage of the other end of the
first core member 10 through a thinned portion m from the second
magnetic material of the other end of the first core member 10 by
shifting entirely the second core member 20 downwards, with left
one stage of one end of the second core member 20 unconnected. The
yoke member 4 has on one side a plurality of projecting edges 4a
similar to the projecting edges 2a on the yoke member 2.
[0080] Reference numeral 30 denotes a third core member formed by
stacking five magnetic materials similar to the first and second
core members 10 and 20, each of which is made up of three yoke
members 5,6 and 7 as many as the first core member 10 connected
through a thinned portion m. One end of the first magnetic material
of the third core member 30 is connected to the other end of the
last magnetic material of the second core member 20 through a
tinned portion m by shifting entirely the third core member 30
downwards. The yoke members 5 and 7 have on one side a plurality of
projecting magnetic teeth 5a and 7a, and the yoke member 6 has on
one side a plurality of projecting edges 6a similar to each
projecting edge 2a and 4a.
[0081] Reference numeral 40 denotes formed by stacking five
magnetic materials similar to the third core member 30 and made up
of a yoke member 8 arranged in such a manner that one end of each
magnetic material of the fourth core member 40 is successively
connected to the second stage of the other end of the third core
member 30 through a thinned portion m from the second magnetic
material of the other end of the third core member 30 by shifting
entirely the fourth core member 40 downwards, with left one stage
of one end of the fourth core member 40 unconnected. The yoke
member 40 has on one side projecting edges 8a similar to each
projecting edge 2a, 4a and 6a. The first, second, third and fourth
core members are independently arranged in a ring and mutually
stacked.
[0082] The method of manufacturing the stacked stator core 50
formed as mentioned above and a stator using this stator core will
now be described.
[0083] First of all, four sheets of magnetic material are formed by
successively forming them into the shape shown in FIG. 3 by
blanking using a successive die, and drilled to form small holes in
the vicinity of the outer contour of corners C1, C2 and C3 of the
corners C1, C2, C3 and C4. Then, slits are formed by cutting and
bending the material between the small holes and the inner contour
to form a bendable thinned portion m between the small holes and
the outer contour in each corner. Also, in corner C4, a slit is
formed between the outer and inner contours by cutting and bending
the material to from the slit running from the inner contour to the
outer contour.
[0084] Secondly, in the same manner as the above, one sheet of
magnetic material is formed into the shape shown in FIG. 4, by
further stacking it on the magnetic material as mentioned above,
and drilled to form small holes in the vicinity of the outer
contour of corners C1, C2 and C4 out of the corners C1, C2, C3 and
C4. Then, slits are formed by cutting and bending the material
between the small holes and the inner contour to form a bendable
thinned portion m between the small holes and the outer contour in
each corner. Also, in corner C3, a slit is formed between the outer
and inner contours by cutting and bending the material to form the
slit running from the inner contour to the outer contour. Then, the
stacked magnetic material is caulked at the places marked with a
circle in FIGS. 3 and 4 to fix and integrate the magnetic material
into the yoke members 5, 6, 7 and 8.
[0085] Subsequently, in the same manner as the above, four sheets
of magnetic material are formed into the shape shown in FIG. 3,
stacked, and drilled to form small holes in the vicinity of the
outer contour of corners C1, C2 and C3, out of the corners C1, C2,
C3 and C4. Then, slits are formed by cutting and bending the
material between the small holes and the inner contour to form a
bendable thinned portion m between the small holes and the outer
contour in each corner. Also, in corner C4, a slit is formed
between the outer and inner contours by cutting and bending the
material, to form the slit running from the inner contour to the
outer contour.
[0086] After that, in the same manner as the above, one sheet of
magnetic material having the shape shown in FIG. 4 is formed,
further stacked on the stacked magnetic material as mentioned
above, and drilled to make small holes in the vicinity of the outer
contour of corners C1, C2 and C4 out of the corners C1, C2, C3 and
C4. Then, slits are formed by cutting and bending the material
between the small holes and the inner contour to form bendable
thinned portion m between the small holes and the outer contour in
each corner. Also, in corner C3, a slit is formed between the outer
and inner contours by cutting and bending the material to form the
slit running from the inner contour to the outer contour. Then, the
stacked magnetic material is caulked at the places marked with a
circle in FIGS. 3 and 4 to fix and integrate the magnetic material
into each of yoke members 1, 2, 3 and 4.
[0087] As mentioned above, a ring made up of yoke members 5 to 8
and another ring made up of yoke members 1 to 4 are stacked in the
state in which the lowest magnetic material of yoke member 4 and
the highest magnetic material of yoke member 5 are connected
through thinned portion m to finish a stator core 50. In the sate
in which a prescribed number of the stacked stator cores 50 are
stacked by a predetermined number of stages, the stacked stator
cores are taken out of a mold as a block.
[0088] Stacked stator cores 50 thus taken out of the mold in the
stacked state are transferred to the next process by a pallet 11 as
shown in FIG. 5. Then, the stacked stator cores 50 are placed on a
tension roller 12, and the core members are successively withdrawn
from the uppermost stacked stator cores in the direction indicated
by an arrow as shown in FIG. 6 to unfold the stacked stator cores.
In the next process, as shown in FIG. 7, the unfolded stacked
stator cores are hung by a hanger 13, and dipped in a coating bath
14 to apply electrocoating. Then, the stacked stator core 50
terminated in the electrocoating process in the unfolded state are
transferred to the next winding process.
[0089] In the winding process, as shown in FIG. 8, a magnet wire 17
drawn out from a receiving drum 16 is wound around the pole teeth
1a, 3a, 5a and 7a by a winding machine 15 in the order of yoke
members 1, 3, 5 and 7, and the terminal of the wire is twined
around the projecting edges 2a, 4a, 6a and 8a of the yoke members
2, 4, 6, and 8, respectively. Subsequently, the yoke members 1 to 4
are wound up by a winding machine 18 in a ring, and as shown in
FIG. 9, by cutting the thinned portion m, through which the
magnetic material of the lowest yoke member 4 and the magnetic
material of the highest yoke member 5 are connected. A stator 60 is
finished, in which a winding 19 is wound around the projecting
edges 1a and 3a of the yoke members 1 and 3 respectively, and a
terminal 19a is twined around the projecting edges 2a and 4a of
yoke members 2 and 4 respectively.
[0090] Similarly, stators 60 are finished successively by cutting
the thinned portion m connected in the yoke members 5 to 8 and the
yoke members 1 to 4 sequence, and successively winding up the yoke
members in a ring.
[0091] As mentioned above, according to the first embodiment, the
stacked stator core 50 is formed by blanking, and cutting and
bending processes shown in FIGS. 3 and 4 repeated for every
prescribed number of magnetic materials using a progressive die.
Then, a plurality of these stacked stator cores are stacked to form
a block, and thus formed block of the stacked stator core 50 is
withdrawn straight from the block for unfolding. After
electrocoating and winding in the unfolded state, the stacked
stator core is successively wound up in a ring again to
consecutively form stators 60. This facilitates the unfolding of
winding, and improves the workability in winding process. At the
same time, it provides a stacked stator core capable of increasing
mass production and the method of manufacturing thereof.
[0092] Naturally, without restricted to the above. Since the bent
portion intervening in the yoke members 1 to 8 is formed by a
thinned portion m made up of a small hole and a slit, the process
therefore becomes easy. Additionally, since the number of the
magnetic material connecting the second and the third core members
20 and 30, and the fourth and the first core members 40 and 10 is
limited to only one, the cutting process becomes easy when winding
up the core as a core in a ring again after the winding process is
done. Moreover, since the magnetic materials are blanked and
caulked at the same time for every yoke members 1 to 8 when
blanking the magnetic materials, the post process can be omitted
after integration. This make it possible to improve the workability
in the assembly process and mass productivity.
[0093] In addition, in the above structure of the stator 60, no
winding is wound around the yoke members 2, 4, 6 and 8, and the
yoke members function as a so-called magnetic balancer. Even if
there is no space for winding the yoke members 2, 4, 6 and 8 by the
reason of arrangement of peripheral devices, the stator can be
used. Moreover, in the above structure of the stator 60, when the
stacked stator core is wound up in a ring after winding, the core
is wound such that the side on which the winding 19 is wound faces
the inside of the core to implement an inner-rotor type stator 60.
Alternatively, the shape of the stacked stator core may be slightly
changed for the wound side to face the outside of the core to form
an outer-rotor type stator 60.
[0094] In the first embodiment, the description is given, assuming
that one stator 60 is made up of the first core member 10 and
second core member 20. However, it is also possible to consider
that as a whole, one stator 60 is formed by one core made up of a
prescribed number of stacked sheet magnetic materials, i.e., one
stator core used for one rotary motor. In other words, as is
apparent from FIG. 2, first of all, four sheet magnetic materials
are stacked such that they are completely overlapped; then new one
sheet magnetic material is stacked over the four stacked sheet
magnetic materials with the new one sheet magnetic material shifted
relative to the above four stacked sheet magnetic materials; and
subsequently one yoke member of the new four stacked sheet magnetic
materials are overlapped over the above overhung part of the one
sheet magnetic material. This forms a stacked stator core 50 made
up of successively stacked stator cores while holding a prescribed
number of stacked layers as a whole.
Second Embodiment
[0095] Second embodiment of the present invention will now be
described with reference to FIGS. 10 to 14. FIG. 10 is a
perspective view of the rotary motor. FIG. 11 is a perspective view
of the stator used for the rotary motor. FIG. 12 is a partially
enlarged view of the unfolded stator. FIG. 13 is a partially
enlarged view of the unfolded stator core. FIG. 14 is an exploded
perspective view of the rotary motor. In FIGS. 10 to 14, reference
numeral 71 denotes a base, reference numeral 72 a rotor, and
reference numeral 73 a stator.
[0096] As shown in FIG. 14, the base 71 is provided with stator
fastening pins 101 having a support flange 101a and an engaged
portion 101b to position and fasten the stator 73, a stator
supporting pin 102 to position the stator 73, coil terminal lands
103,104 and base fastening holes 105 for fastening the base 71. A
rotor 72 is provided with a shaft 201 engaged and supported by the
base 71 in the center of the base 71. The base 71 is pivotally
provided with a turntable 202 engaged and fixed by the shaft 201
and a ring-shaped rotor magnet 203 fixed to the periphery of the
turntable 202 and magnetized such that the periphery of the rotor
magnet 203 has multipole.
[0097] As shown in FIGS. 11 to 13, a stator 73 is made up of a
stator core 300 formed by stacking sheet magnetic materials and
driving coils 350 whose magnetic pole teeth 302 are wound by a
wire. In addition, the stator core 300 is provided with yoke
members 301 made up of magnetic pole teeth 302 of the number
provided in proportion to the number of driving phase and yokes 303
having tooth-shaped magnetic pole teeth 302, a stepped yoke member
309 provided with magnetic pole teeth 302 and yoke 303 similar to
other yoke members 301 and having a sheet magnetic material
partially not connected with other yoke members 301, bent portions
304 connecting the yoke members, stator positioning protrusions 305
arranged opposed to each other on both sides of the bent portion
304 in the same direction as that of magnetic pole teeth 302,
caulkings 306, 307 to fix and integrate the stacked sheet magnetic
materials, and core connecting portions 308 provided at the ends of
the stator core 300, and a driving coil 350 wound around each
magnetic pole teeth 302.
[0098] Stator positioning protrusions 305 are provided for forming
a hole with which stator fastening pins 101 are engaged when the
stator 73 is arranged in a ring as shown in FIGS. 10 and 11. In
other words, when the stator 73 is arranged in a ring, one stator
positioning protrusion 305 (a first positioning hole) provided at
the end of one yoke member 301 and the other stator positioning
protrusion 305 (a second positioning hole) provided at the end of
the other yoke member 301 adjacent to the one yoke member 301 are
bent at the bent portion 304 as a fulcrum, and thereby two stator
positioning protrusions 305 move to the position in which the
protrusions oppose each other to form a hole to engage with the
stator fastening pin 101.
[0099] Similarly, core connecting portions 308 are provided to
engage the ring-shaped stator 73 with the stator supporting pin 102
in such a manner that a hole is formed with the core connecting
portions 308 at both ends of the core opposing each other.
Therefore, the engagement of the positioning holes and the stator
fastening pins 101 easily fixes the stator 73 on the base 71.
[0100] Here, as shown in the sectional view of FIG. 2 in the first
embodiment, the stepped yoke members, i.e., the fourth yoke members
4, 8 in FIG. 2 are formed by stacking the same number (five) of
sheet magnetic materials as that of the other yoke members, i.e.,
the first to third yoke members 1 to 3, 5 to 7 in FIG. 2. For this
reason, the stepped yoke members are shifted from the other yoke
members by one sheet magnetic material in the stacking direction,
and a difference in level (projection) is provided relative to the
other yoke members.
[0101] Coil terminals 351 at one end side of each phase of the
driving coils 350 shown in FIG. 10 are led through the lower part
of the stepped yoke member 309 and soldered to the coil terminal
land 103. Coil terminals at the other end of each phase are
twisted, combined and soldered to the coil terminal land 104 as a
common coil terminal 352.
[0102] In order to arrange the stator 73 in a ring as shown in
FIGS. 10 and 11 or straight as shown in FIG. 12, the bent portions
304 are provided at each connecting part between the yoke members
so as to make the yoke members 301 or the stepped yoke member 309
bendable. Additionally, each magnetic pole teeth 302 of the yoke
members 301 and stepped yoke member 309 are provided so as to make
the magnetic pole teeth 302 parallel to each other within each of
the yoke members.
[0103] A rotary motor 80 so arranged as above can rotate the rotor
72 by feeding a prescribed amount of current to each driving coil
350. Moreover, the provision of the stepped yoke member 309 exerts
the moment of a force in the rotor 72 in which the rotation axis
201 inclines toward the stator 73 because the forces of attraction
acting on the rotor 72 are different between the yoke members 301
and stepped yoke members 309 in the direction of the rotation axis
201 of the rotor 72. As a result, it is possible to stabilize the
rotation of the rotor 72 even when an oscillation or the like is
applied to the rotary motor 80.
[0104] In addition, the coil terminals 351 are led through the
lower part of the stepped yoke member 309 and soldered to the coil
terminal lands 103. As a result, the coil terminal 351 can be led
through a more larger space than the lower part of the other yoke
members 301, improving productivity in wiring.
[0105] The method of manufacturing the above rotary motor 80 will
now be described.
[0106] First of all, the stator core 300 for the rotary motor 80
will be described with reference to FIGS. 15 to 18. FIG. 15 is a
perspective view of the stacked stator core for the stator core 300
of the rotary motor 80. FIG. 16 is a perspective view of the
partially exploded stacked stator core. FIG. 17 is a schematic view
of stator cores with extremely elongated between the stator core at
connection parts. FIG. 18 is a perspective view showing the state
how the sheet magnetic materials of the stacked stator core are
stacked.
[0107] Referring to FIG. 15, reference numeral 50 denotes a stacked
stator core formed by stacking a plurality of stator cores 300 in a
ring and each stator core 300 is successively connected through
stator core connecting portions (interconnection portions) 401.
Further, as shown in FIG. 16, the stator cores 300 can be
successively unfolded straight by bending the bent portions 304. As
shown in FIGS. 16 and 17, a stator core made up of portion 401
consists of a bent portion 304 provided between a stepped yoke
member 309 and the stator core 300 adjacent to the stepped yoke
member 309, in the state of stacked stator core 50. As shown in
FIG. 18, such stacked stator core 50 can be manufactured by
mutually overlapping the same magnetic materials where a first
divided portion 411 thereof is provided at the same place, i.e.,
stacked core 412 made up of four magnetic material cores 410
stacked such that the first divided portions 411 thereof are placed
at the same position and a magnetic material core 420 having the
same shape as that of magnetic material core 410 and a second
divided portion 421 at the position shifted by 60.degree.. The
angle of 60.degree. is calculated based on the fact that since in
the second embodiment, six yoke members (five yoke members 301 and
one stepped yoke member) in total have been provided, the angle
made with one yoke member is 60.degree.
(360.degree..div.6=60.degree.). Here, in the above description, the
case is shown in which the shift is done in an amount of one yoke
member 301. Alternatively, if a stacked stator core 50 is formed by
shifting the magnetic material core in the amount of a plurality of
yoke members, for instance, two yoke members 301 (that is, by
120.degree. in the second embodiment), the same effect may also be
obtained.
[0108] In FIG. 18, the core connecting portion 401 corresponds to
the bent portion 304 in the magnetic material core 420. When the
part 309a adjacent to the second divided portion 421 in the
magnetic material core 420 is stacked, stepped yoke member 309 is
formed. When cut at the stator core connecting portion 401, each
magnetic material core 410 and 420 is connected with caulkings 306
and 307 as shown in FIG. 13.
[0109] Application of insulation coating to the stacked stator core
50 will next be described with reference to FIGS. 19 and 20. FIG.
19 is a schematic view showing the application of insulation
coating to the stacked stator core 50. FIG. 20 is a partially
enlarged view of the stacked stator core 50.
[0110] Referring to FIG. 19, reference numeral 74 denotes an
electrocoating bath, and coating liquid 75 is being filled therein.
An elongated stacked stator core 50 is dipped in the coating liquid
75. Application of a voltage between an electrode (not shown)
placed in the coating liquid 75 and the stacked stator core 50
forms insulation coating film 430 over the stacked stator core 50.
In order to enable the stacked stator core 50 to unfold by the
bending bent portion 304 as shown in FIG. 16, a gap in opening 305a
between the ends of stator positioning protrusions 305 opposing
each other before coating have been previously set such that the
relationship of a>2b is kept with respect to the thickness b of
the insulation coating film 430, not to close the opening 305a by
the insulation coating. Insulation coating using cationic
electrocoating, for instance, is popular as the insulation coating
method.
[0111] Wiring of the driving coils 350 wound around the stacked
stator core 50 and mounting of the wire-wound stator 73 on the base
71 will be described with reference to FIG. 14, FIGS. 21 and 22.
FIG. 21 is a perspective view showing the steps in which the stator
cores 300 are divided from the stacked stator core 50 and the
driving coils 350 are wound around the divided stator core 300.
FIG. 22 is a perspective view showing the steps in which the
driving coils 350 are wound around the divided stator core 300 and
unfolded a stator 73 is formed in a ring. FIG. 14 is an exploded
perspective view of the step in which the stator 73 is mounted on
the base 71.
[0112] As shown in FIGS. 21 and 22, the stator cores 300 are
unfolded from the stacked stator core 50 and divided at the stator
core connecting portion 401 (FIG. 16). FIG. 22A is a view of a
divided stator core 300. Then, the driving coils 350 are
simultaneously wound around the magnetic pole teeth 302 of the yoke
members 301 by a winding machine 360 (FIG. 22B). The wire-wound
stator 73 is bent at the bent portions 304 and arranged in a ring
(FIG. 22C). As shown in FIG. 14, the ring-shaped stator 73 is
mounted on the base 71. A rotary motor 80 is finished by soldering
coil terminals 351 and a common coil terminal 352 with coil
terminal lands 103 and a coil terminal land 104, respectively.
[0113] Adoption of such a method of manufacturing stators used for
rotary motors improves both the workability in the winding process,
and the mass productivity of the stators and rotary motors.
[0114] The shape of the stator core 300 of the above rotary motor
80 will be described with reference to FIGS. 23 and 24. FIG. 23 is
a partially enlarged view and a corresponding sectional view in the
vicinity of the bent portion 304 of the stator core 300. FIG. 24 is
a plan view showing the angle pitches of the magnetic pole teeth
302. The width c of bent portion 304 in the diameter direction is
set such that the width c satisfies the relationship of
1.5t.ltoreq.c.ltoreq.2.5t for the thickness t of one stacked sheet
magnetic material. The reason why this relationship is established
is to prevent the bent portion 304 from being divided when the
stator core 300 is unfolded straight by bending the bent portion
304 to wind the driving coil 350, and subsequently the stator 73 is
arranged in a ring by again bending the bent portion 304 of the
stator core 300. An experimental investigation of the relationship
between the width c and the thickness t of the bent portion 304 in
terms of the bending times of the bent portion 304 revealed that
the the bent portion 304 can endure several times of bending if the
width c of the bent portion 304 is 1.5t or more. However, it turned
out that inasmuch as the width c of bent portion 304 is set up too
large, the bending at the prescribed position of the bent portion
304 is sometimes failed and so can not take the arrangement in a
ring when one tries to make the stator 73 in a ring. It is
experimentally proved that the suitable width c of bent portion 304
is 2.5 t or less.
[0115] Moreover, as shown in FIG. 24, it is possible to reduce the
cogging torque by setting the electrical angle pitches .theta.b
between magnetic pole teeth 302 located within one yoke member 301
and the electrical angle pitch .theta. between the magnetic pole
tooth 302 located within the one yoke member 301 and a magnetic
pole tooth 302 within the yoke member 301 adjacent to the one yoke
member 301 so as for the electrical angle pitches .theta.b and
.theta. to satisfy the relationship of .theta..noteq..theta.b.
However, because the driving power of the rotary motor is lowered
when the relationship between .theta.b and .theta. is significantly
altered each other, it is preferable that the suitable shift amount
between both the electrical angle pitches is 10.degree. or less in
electric angle. That is, the electric angle .theta. satisfying the
relationship of
.theta.b-10.degree..ltoreq..theta..ltoreq..theta.b+10- .degree. and
.theta..noteq..theta.b is advisable.
[0116] In the second embodiment, the stator core 300 is divided
from the stacked stator core 50 and the driving coils 350 are wound
around the stator core 300. Naturally, as shown in FIG. 25, if the
stator 73 is manufactured by dividing the stator core 300 from the
stacked stator core 50 after the driving coils 350 are wound around
the stator core 300, the same effect can be obtained. That is, it
is needless to say that the workability in the winding process, and
the productivity of the stators and rotary motors can be
improved.
Third Embodiment
[0117] In above second embodiment, a stator 73 is mounted on a
rotary motor 80 with a difference in level of one sheet magnetic
material (magnetic material cores 410, 420) provided between the
stepped yoke member 309 and the yoke members 301.
[0118] A method of reducing the influence of the difference in
level between these yoke members caused by the stepped yoke member
309 will be described. Like or equivalent members as that of the
second embodiment are given like reference numerals, and thus the
description thereof is omitted for brevity's sake.
[0119] FIG. 26 is a sectional view showing the state in which a
cover table 210 is provided over the rotor 72 of the rotary motor
80 in the second embodiment to keep the invasion of dust or the
like out of the cavity between the rotor magnet 203 and the stator
73. In FIG. 26, reference numeral 110 denotes a bearing that
engages with a shaft 201 installed in the base 71. In this case, a
difference in level is provided between the height Ha of yoke
member 301 and the height Hd of stepped yoke member 309. When the
cover table 210 is provided over the upper surface of the driving
coil 350 wound around the magnetic pole teeth 302 of the yoke
member 301 through a prescribed space e, the cover table 210 comes
into contact with the driving coil 350 wound around the magnetic
pole teeth 302 of the stepped yoke member 309. As a result, the
prescribed operation of the rotary motor 80 is not accomplished, or
the rotary motor 80 does not rotate. One of the solutions to this
problem is to increase the space e. However, such a solution gives
rise to difficulties in thinning the rotary motor 80 because the
thickness of the motor itself increases.
[0120] In the third embodiment, a method of removing the influence
of the stepped yoke member 309 while avoiding the trouble of
increasing thickness of rotary motor 80.
[0121] One of effective methods is to reduce the number of winding
of the driving coil 350 wound around the magnetic pole teeth 302 of
the stepped yoke member 309 compared with the number of winding of
the driving coil 350 wound around the magnetic pole teeth 302 of
the yoke member 301 as shown in FIG. 27.
[0122] Another method is to mount the stator 73 onto the base 71
with a gradient as shown in FIG. 28 such that the height of the
driving coil of the stepped yoke member 309 is lower than the
height thereof shown in FIG. 26. Then, the stator 73 is arranged
such that the height Hf of the uppermost part of the driving coil
350 wound around the magnetic pole teeth 302 of yoke member 301 is
identical with the height Hh of the uppermost part of driving coil
350 wound around the magnetic pole teeth 302 of the stepped yoke
member 309.
[0123] In addition, still another method is to press forming the
stator core 300 having the stepped yoke member 309 (FIG. 29A) as
shown in FIG. 29 such that the height of the stepped yoke member
309 becomes flush with that of the other yoke members 301 (FIG.
29B) to eliminate the difference in level of the stepped yoke
member 309. After that, the driving coils 350 are formed by winding
a wire around each of magnetic pole teeth 302 and a stator 73 is
formed by bending each yoke member 301 in a ring as shown in FIG.
30. Subsequently, the stator 73 are mounted and fixed onto the base
71 as shown in FIG. 31. This method of making the height of the
stepped yoke member 309 flush with that of the yoke member 301 is
extremely effective.
[0124] As mentioned above, thin rotary motors 80 can be easily
implemented when the influence of the stepped yoke member 309 is
removed by the above methods of changing the number of winding of
the driving coil 350, mounting the stator 73 to the base 71 by
inclining the stator 73, and press forming the stepped yoke member
309.
Fourth Embodiment
[0125] As a structure in which yoke members are overlapped one
another in the stator core, the stacked stator and rotary motor of
the fourth embodiment 4 which increases mounting of the stator 73
on the base 71 will next be described with reference to FIGS. 32 to
40. FIG. 32 is a perspective view of the rotary motor. FIG. 33 is a
perspective view of the stator for the rotary motor. FIG. 34 is a
partially enlarged view of the unfolded stator. FIG. 35 is a
partially enlarged view showing the state in which the stator core
is unfolded. FIG. 36 is a perspective view showing the state in
which the stacked stator core is partially unfolded. FIG. 37 is a
schematic view showing the state in which the stacked stator core
is elongated. FIG. 38 is a perspective view showing the state in
which the sheet magnetic materials of the stacked stator core are
stacked. FIG. 39 is a perspective view showing the steps in which
the stator core 300 is divided from the stacked stator core 50, the
driving coils 350 are wound around the stacked stator core 50, and
subsequently arranged in a ring. FIG. 40 is a perspective view
showing the step in which the stator 73 is mounted on the base 71.
Like or equivalent members as that of the second embodiment are
given like reference numerals and thus the description thereof is
omitted for brevity's sake.
[0126] As shown in FIG. 40, the base 71 is provided with stator
fastening pins 101 having a support flange 101a and an engaging
portion 101b for positioning and fastening the stator 73, a stator
supporting pin 102 for positioning the stator 73, and a rotor 72
pivotally connected thereto.
[0127] As shown in FIGS. 32 to 34, and FIG. 40, a stator 73 is made
up of a stator core 300 formed by stacking sheet magnetic
materials, and driving coils 350.
[0128] The stator core 300 is provided with yoke members 301 made
up of magnetic pole teeth 302 that is provided in proportion to the
number of driving phase and yokes 303 having tooth-shaped magnetic
pole teeth 302, bent portions 304 for connecting the yoke members
301, stator positioning protrusions 305 arranged opposed to each
other on both sides of the bent portion 304 in the same direction
as that of the magnetic pole teeth 302, core connecting portions
321, 322 having punched thereon connecting and fixing holes 323,
324, provided at the ends of the stator core 300 such that the core
connecting portions 321, 322 are overlapped one another when the
stator core 300 is arranged in a ring, and a stepped yoke member
309 is provided with the magnetic pole teeth 302 and yokes 303 as
in other yoke members 301 and having partially a sheet magnetic
material not connected with other yoke members 301, with each of
the driving coils are being wound around the magnetic pole teeth
302.
[0129] Stator positioning protrusions 305 are provided so that
holes engaging with stator fastening pin 101 are formed in the
state in which the stator 73 is arranged in a ring. Moreover, as
shown in FIG. 32, FIGS. 33 and 40, the core connecting portions 321
and 322 are also provided such that the core connecting portions
321, 322 located at both ends are overlapped one another and the
connecting and fixing holes 323 and 324 engage with the stator
supporting pin 102 when the stator 73 is arranged in a ring.
[0130] The stepped yoke member 309 and other yoke members 301 have
the same number (five) of stacked sheet magnetic materials, and
therefore a difference in level of a sheet magnetic material is
provided because the stepped yoke member 309 is shifted by a sheet
magnetic material from other yoke members 301 toward the upper
surface relative to the stacking direction.
[0131] The rotary motor 80 so arranged as above can rotate rotor 72
by feeding a prescribed amount of current through each driving coil
350. Moreover, the provision of stepped yoke member 309 makes
difference in the forces of attraction acting on the rotor 72
between yoke members 301 and stepped yoke members 309 in the
direction of the rotation axis 201 of rotor 72. As a result, the
moment of a force of the direction in which the rotation axis 201
inclines toward the stator 73 is exerted on rotor 72, and it
becomes possible to stabilize the rotation of rotor 72 even when an
oscillation or the like is applied to the rotary motor 80.
[0132] Moreover, the core connecting portions 321,322 having
connecting and fixing holes 323, 324 are provided at both ends of
the stator core 300 so that the stator supporting pin 102 engages
with the connecting and fixing hole 323, 324. Therefore, the
workability and positioning are improved when the stator 73 is
arranged in a ring and fixed on the base 71, and it becomes
possible to firmly fix the stator 73 on the base 71.
[0133] The method of manufacturing such rotary motor 80 will now be
described.
[0134] First of all, a stator core 300 used for the rotary motor 80
will be described with reference to FIGS. 36 to 38. Referring to
the FIGS. 36 to 38, reference numeral 50 denotes a stacked stator
core formed in such a manner that a plurality of stator cores 300
having a ring are stacked and each the stator core 300 is
successively connected through stator core connecting portions 401.
As shown in FIG. 36, stator cores 300 can be unfolded straight by
bending bent portions 304.
[0135] As shown in FIG. 38, such stacked stator core 50 is
manufactured by successively overlapping the following parts: a
stacked core A453 formed by overlapping two magnetic material cores
452 having a first divided portion 451 provided in the vicinity of
the part corresponding to the core connecting portion 321, which
are the same to each other and are overlapped such that the first
divided portions 451 thereof are placed at the same position; a
stacked core B456 formed by overlapping two magnetic material cores
455 that are in mirror image relation to the magnetic material core
452, i.e., correspond to the material core 452 turned reversely at
an angle of 180 degree, have a second divided portion 454 provided
in the vicinity of the part corresponding to the core connecting
portion 322, and overlapped one another; and a magnetic material
core 458 having a partially notched stator core connecting portion
401 provided for omitting connecting and fixing holes 323, 324 at
the part corresponding to the position of bent portion 304 and a
third divided portion 457 provided at bent portion 304 located in
the position away from the stator core connecting portion 401 by a
distance of one yoke member. In FIG. 18, reference numeral 301a
denotes the part to be yoke member 301 when stacked, and the
numeral 309a denotes the part to be stepped yoke member 309 when
stacked, respectively.
[0136] The stacked core A 453, the stacked core B 456, and the
magnetic material core 458 are connected to each other by caulkings
306, 307 as shown in FIG. 35 when cut at stator core connecting
part 401. Winding of the driving coils 350 wound around the stacked
stator core 50 and mounting of the stator 73 on the base 71 are
carried out in the same manner as the second embodiment as shown in
FIG. 36, FIGS. 39 and 40. As shown in FIG. 36, stator cores 300 are
unfolded from the stacked stator core 50 and divided at the stator
core connecting portion 401. Then, the driving coils 350 are
consecutively wound around the magnetic pole teeth 302 of the yoke
members 301 by a winding machine 360. The wire-wound stator 73 is
bent at the bent portions 304 and arranged in a ring. As shown in
FIG. 40, the ring-shaped stator 73 is mounted on the base 71. A
rotary motor 80 is finished by soldering coil terminals 351 and a
common coil terminal 352 with coil terminal lands 103 and 104,
respectively. The adoption of the above method of manufacturing
rotary motors improves workability in the winding process and the
productivity of rotary motors. In addition to the above effects,
when the stators 73 are arranged in a ring and fixed on the base
71, the workability and positioning are improved, and it becomes
possible to firmly fix the stators 73 on the bases 71.
Fifth Embodiment
[0137] In the above second and fourth embodiments, in order to
manufacture a stacked stator core 50, sheet magnetic materials are
stacked for forming the yoke members 301 (including the stepped
yoke member 309) located on both sides of the stator core
connecting portion 401 connecting the stator cores 300, and joined
by caulking 306, 307. For this reason, a stepped yoke member 309 is
formed after the stator cores are divided at the stator core
connecting portion 401. The fifth embodiment provides connecting
means for connecting stator cores 300 in which no difference in
level is provided between the magnetic pole teeth 302 around which
the driving coils 350 are wound.
[0138] The fifth embodiment will be described with reference to
FIGS. 41 to 43.
[0139] FIG. 41 is a perspective view showing the state in which the
stacked stator core 50 is partially unfolded. FIG. 42 is a
schematic view showing the state in which the stator core is
elongated. FIG. 43 is a perspective view showing the steps in which
the stator core 300 is divided from the stacked stator core 50 and
the driving coils 350 are wound around the stator core 300. Like or
equivalent members as that of the second and fourth embodiments are
given like reference numerals and thus the description thereof is
omitted for brevity's sake.
[0140] In FIGS. 41 and 42, reference numeral 401 denotes the stator
core connecting portion. In the sheet magnetic materials provided
on one end side of the stator core connecting portion 401 and
placed on yoke members 301, a connecting leaf 470 having the
similar shape to that of bent portion 304 is connected with a yoke
member 301 by a caulking 471, and the opposing end (opposing the
connecting leaf 470) is made up of magnetic pole teeth 302 and a
yoke 303 forming the yoke member 301. In other words, the
connecting leaf 470 functions as an interconnecting portion. Such
an arrangement as mentioned above brings about the state shown in
FIG. 43, when a stator core 300 is divided from the stacked stator
core 50 at the stator core connecting portion 401. That is,
although the connecting leaf 470 yet remains at the end of the
stator core 300, there is provided no difference in level between
yoke members 301 in the part of magnetic pole teeth 302 around
which the driving coils 350 are wound. Therefore, a slim stator 73
having no difference in level can be provided, even through the
stacked stator core 50 is used.
Sixth Embodiment
[0141] In the above second and fourth embodiments, the bent portion
304 is formed at the part having a thickness thinner than that of
yoke 303 made up of the yoke member 301. Alternatively, a bent
portion that is more easily bent will next be described with
reference to FIGS. 44 to 46.
[0142] FIG. 44 is a plan view showing the state in which the stator
core 300 is arranged in a ring. FIG. 45 is a partial plan view
showing the state in which the yoke member 301 is unfolded in the
bent portion. FIG. 46 is a sectional view of the bent portion. Like
or equivalent members as that of the second and fourth embodiments
are given like reference numerals and thus the description thereof
is omitted for brevity's sake.
[0143] In FIGS. 44 to 46, reference numeral 340 denotes a bent
portion connecting yoke members 301. In the center of the bent
portion 340 positioning fastening holes 341 are provided for
mounting and fixing a stator 73 on a base 71. As shown in FIG. 46,
one to four layers of sheet magnetic materials are stacked such
that recesses 342 and protrusions 343 formed by half blanking the
stacked sheet magnetic materials so as to engage each other. In the
fifth layer of sheet magnetic material (the uppermost layer in FIG.
46) is provided a hole 344 engaging with the protrusions 343 formed
in the fourth layer of sheet magnetic material. In addition, in the
sheet magnetic materials of each layer are provided gaps 345 having
a prescribed width in the vicinity of bent portions 340 so as for
the bent portions 340 to be easily bent. A so-called joint
structure constructed by engagement of the recesses 342 and
protrusions 343 is arranged so as for yoke members 301 to be easily
unfolded.
[0144] As mentioned above, letting the bent portion 340 to have a
joint structure makes it possible to eliminate the fracture of the
bent portion 340 due to the fatigue of bent portion 340, thereby
increasing the reliability of the rotary motor 80, in the core
structure like the stacked stator core 50 where it suffers from the
frequent bending in the bent portion such as the unfold of stator
core 300 or the restore to the original arrangement of the stator
73 in a ring.
Seventh Embodiment
[0145] A floppy disk drive unit equipped with the rotary motor 80
manufactured based on the stacked stator core 50 according to the
above embodiments will now be described with reference to FIG.
47.
[0146] Referring to FIG. 47, reference numeral 601 denotes a
loading unit, reference numeral 602 a magnetic head, reference
numeral 603 a control board, reference numeral 604 a voice coil
motor, and reference numeral 605 a floppy disk, respectively.
[0147] A rotary motor 80 manufactured based on the stacked stator
core 50 is mounted on the base of floppy disk drive unit nearly in
the center of the disk drive unit. The magnetic record medium
pivotally installed within the floppy disk 605 is rotated at a
prescribed number of rotations by means of the rotating torque of
the rotary motor 80. The reading and writing of data from and to
such a floppy disk 605 is done via the magnetic head 602. The voice
coil motor 604 causes the magnetic head 602 to seek in the radius
direction of floppy disk 605. The rotary motor 80 and the voice
coil motor 604 are accurately controlled by the electric circuit
provided on the control board 603.
[0148] The application of the rotary motor 80 according to the
present invention to the floppy disk drive unit makes it possible
to slim the floppy disk drive unit and cut down the cost of the
floppy disk drive unit.
[0149] The description of the above embodiment is made by way of
the floppy disk drive unit. However, the similar effect may be
obtained by application of the rotary motor 80 according to the
present invention to other disk drive units having a drive
mechanism actuated by a rotary motor, hard disk drive units, CD-ROM
drive units or the like, for instance.
Industrial Applicability
[0150] As mentioned above, the stacked stator core according to the
present invention provides stacked stator cores enabling easy
transportation of the materials, easy mounting onto the winding
machine, easy unfolding and dividing of the stator cores for
winding, and the assembly work. Further, it allows manufacture of
rotary motors superior in mass productivity from the stacked stator
core according to the present invention.
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